Accommodating intraocular lens having T-shaped haptics

ABSTRACT

An accommodating intraocular lens having anteriorly and posteriorly movable extended portions, such as T-shaped haptics, extending from a central optic to be implanted within a natural capsular beg of a human eye with the extended portions positioned between an anterior capsular rim and a posterior capsule of the bag, whereby during a post-operative healing period, fibrosis occurs about the extended portions to fixate the lens in the bag in a manner such that subsequent natural contraction and relaxation of the ciliary muscle moves the optic to provide vision accommodation of increased accommodation amplitude and diopters of accommodation.

RELATED APPLICATIONS

This application is a continuation-in-part of my application Ser. No.08/388,735, filed Feb. 15, 1995, now abandoned.

Reference is made to my copending application Ser. No. 08/640,118, whichis a continuation, with intermediate continuation applications of myU.S. Pat. No. 5,476,514. Reference is also made to my U.S. Pat. No.5,496,366.

BACKGROUND OF THE INVENTION

This invention relates generally to intraocular lenses to be implantedwithin a natural capsular bag in the human eye formed by evacuation ofthe crystalline matrix from the natural lens of the eye through aanterior capsulotomy in the lens. The invention relates moreparticularly to novel accommodating intraocular lenses of this kindhaving a number of improved features including, most importantly,increased amplitude or diopters of accommodation.

The human eye has an anterior chamber between the cornea and iris, aposterior chamber behind the iris containing a crystalline lens, avitreous chamber behind the lens containing vitreous humor, and a retinaat the rear of the vitreous chamber. The crystalline lens of a normalhuman eye has a lens capsule attached about its periphery to the ciliarymuscle of the eye by zonules and containing a crystalline lens matrix.This lens capsule has elastic optically clear anterior and posteriormembrane-like walls commonly referred to by ophthalmologists as anteriorand posterior capsules, respectively. Between the iris and the ciliarymuscle is an annular crevice-like space called the ciliary sulcus.

The human eye possesses natural accommodation capability. Naturalaccommodation capability involves relaxation and contraction of theciliary muscle of the eye by the brain to provide the eye with near anddistant vision. This ciliary muscle action is automatic and shapes thenatural crystalline lens to the appropriate optical configuration forfocusing on-the retina the light rays entering the eye from the scenebeing viewed.

The human eye is subject to a variety of disorders which degrade ortotally destroy the ability of the eye to function properly. One of themore common of these disorders involves progressive clouding of thenatural crystalline lens matrix resulting in the formation of what isreferred to as a cataract. It is now common practice to cure a cataractby surgically removing the cataractous human crystalline lens andimplanting an artificial intraocular lens in the eye to replace thenatural lens. The prior art is replete with a vast assortment ofintraocular lenses for this purpose.

Intraocular lenses differ widely in their physical appearance andarrangement. This invention is concerned with intraocular lenses of thekind having a central optical region or optic and haptics which extendoutward from the optic and engage the interior of the eye in such a wayas to support the optic on the axis of the eye.

Up until the late 1980s, cataracts were surgically removed by eitherintracapsular extraction involving removal of the entire human lensincluding both its outer lens capsule and its inner crystalline lensmatrix, or by extracapsular extraction involving removal of the anteriorcapsule of the lens and the inner crystalline lens matrix but leavingintact the posterior capsule of the lens. Such intracapsular andextracapsular procedures are prone to certain post-operativecomplications which introduce undesirable risks into their utilization.Among the most serious of these complications are opacification of theposterior capsule following extracapsular lens extraction, intraocularlens decentration, cystoid macular edema, retinal detachment, andastigmatism.

An improved surgical procedure called anterior capsulotomy was developedto alleviate the above and other post-operative complications and risksinvolved in intracapsular and extracapsular cataract extraction. Simplystated, anterior capsulotomy involves forming an opening in the anteriorcapsule of the natural lens, leaving intact within the eye a capsularbag having an elastic posterior capsule, an anterior capsular remnant orrim about the anterior capsule opening, and an annular crevice, referredto herein as a cul-de-sac, between the anterior capsule remnant and theouter circumference of the posterior capsule. This capsular bag remainsattached about its periphery to the surrounding ciliary muscle of theeye by the zonules of the eye. The cataractous natural lens matrix isextracted from the capsular bag through the anterior capsule opening byphacoemulsification and aspiration or in some other way after which anintraocular lens is implanted within the bag through the opening.

A relatively recent and improved form of anterior capsulotomy known ascapsulorhexis is essentially a continuous tear circular or roundcapsulotomy. A capsulorhexis is performed by tearing the anteriorcapsule of the natural lens capsule along a generally circular tear linesubstantially coaxial with the lens axis and removing the generallycircular portion of the anterior capsule surrounded by the tear line. Acontinuous tear circular capsulotomy or capsulorhexis, if performedproperly provides a generally circular opening through the anteriorcapsule of the natural lens capsule substantially coaxial with the axisof the eye and surrounded circumferentially by a continuous annularremnant or rim of the anterior capsule having a relatively smooth andcontinuous inner edge bounding the opening. When performing a continuoustear circular capsulorhexis, however, the anterior rim may sometimes beaccidentally torn, nicked, or otherwise ruptured, which renders the rimprone to tearing when the rim is stressed, as it is during fibrosis asdiscussed below.

Another anterior capsulotomy procedure, referred to as an envelopecapsulotomy, involves cutting a horizontal incision in the anteriorcapsule of the natural lens capsule, then cutting two vertical incisionsin the anterior capsule intersecting and rising from the horizontalincision, and finally tearing the anterior capsule along a tear linehaving an upper upwardly arching portion which starts at the upperextremity of the vertical incision and continues in a downward verticalportion parallel to the vertical incision which extends downwardly andthen across the second vertical incision. This procedure produces agenerally archway-shaped anterior capsule opening centered on the axisof the eye. The opening is bounded at its bottom by the horizontalincision, at one vertical side by the vertical incision, at its oppositevertical side by the second vertical incision of the anterior capsule,and at its upper side by the upper arching portion of the capsule tear.The vertical incision and the adjacent end of the horizontal incisionform a flexible flap at one side of the opening. The vertical tear edgeand the adjacent end of the horizontal incision form a second flap atthe opposite side of the opening.

A third capsulotomy procedure, referred to as a beer can or can openercapsulotomy, involves piercing the anterior capsule of the natural lensat a multiplicity of positions along a circular line substantiallycoaxial with the axis of the eye and then removing the generallycircular portion of the capsule circumferentially surrounded by theline. This procedure produces a generally circular anterior capsuleopening substantially coaxial with the axis of the eye and boundedcircumferentially by an annular remnant or rim of the anterior capsule.The inner edge of this rim has a multiplicity of scallops formed by theedges of the pierced holes in the anterior capsule which render theannular remnant or rim prone to tearing radially when the rim isstressed, as it is during fibrosis as discussed below.

Intraocular lenses also differ with respect to their accommodationcapability and their placement in the eye. Accommodation is the abilityof an intraocular lens to accommodate, that is, to focus the eye fornear and distant vision. Certain patents describe alleged accommodatingintraocular lenses. Other patents describe non-accommodating intraocularlenses. Most non-accommodating lenses have single focus optics whichfocus the eye at a certain fixed distance only and require the wearingof eye glasses to change the focus. Other non-accommodating lenses havebifocal optics which image both near and distant objects on the retinaof the eye. The brain selects the appropriate image and suppresses theother image, so that a bifocal intraocular lens provides both nearvision and distant vision sight without eyeglasses. Bifocal intraocularlenses, however, suffer from the disadvantage that each bifocal imagerepresents only about 40% of the available light, and a remaining 20% ofthe light is lost in scatter.

There are four possible placements of an intraocular lens within theeye. These are (a) in the anterior chamber, (b) in the posteriorchamber, (c) in the capsular bag, and (d) in the vitreous chamber. Theintraocular lenses disclosed herein are for placement in the capsularbag.

SUMMARY OF THE INVENTION

This invention provides an improved accommodating intraocular lens to beimplanted within a capsular bag of a human eye which remains intactwithin the eye after removal of the crystalline lens matrix from thenatural lens of the eye through an anterior capsule opening in thenatural lens. This anterior opening is created by performing an anteriorcapsulotomy, preferably an anterior capsulorhexis, on the natural lensand is circumferentially surrounded by an anterior capsular rim which isthe remnant of the anterior capsule of the natural lens. An improvedaccommodating intraocular lens according to the invention includes acentral optic having normally anterior and posterior sides and extendedportions spaced circumferentially about and extending generally radiallyout from the edge of the optic. These extended portions have inner endsjoined to the optic and opposite outer ends movable anteriorly andposteriorly relative to the optic. To this end, the extended portionsare either pivotally or flexibly hinged at their inner ends to the opticor are resiliently bendable throughout their length. In this disclosure,the terms “flex”, “flexing”, “flexible”, and the like are used in abroad sense to cover both flexibly hinged and resiliently bendableextended portions. The terms “hinge”, “hinged”, “hinging”, and the likeare used in a broad sense to cover both pivotally and flexibly hingedextended portions.

The lens is surgically implanted within the evacuated capsular bag of apatient's eye through the anterior capsule opening in the bag and in aposition wherein the lens optic is aligned with the opening, and theouter ends of the lens extended portions are situated within the outerperimeter or cul-de-sac of the bag. The lens has a radial dimension fromthe outer end of each extended portion to the axis of the lens opticsuch that when the lens is implanted within the capsular bag, the outerends of the extended portions engage the inner perimetrical wall of thebag without stretching the bag.

After surgical implantation of the accommodating intraocular lens in thecapsular bag of the eye, active endodermal cells on the posterior sideof the anterior capsule rim of the bag cause fusion of the rim to theelastic posterior capsule of the bag by fibrosis. This fibrosis occursabout the lens extended portions in such a way that these extendedportions are effectively “shrink-wrapped” by the fibrous tissue in sucha way as to form radial pockets in the fibrous tissue which contain theextended portions with their outer ends positioned within the outercul-de-sac of the capsular bag. The lens is thereby fixated within thecapsular bag with the lens optic aligned with the anterior capsuleopening in the bag. The anterior capsule rim shrinks during fibrosis,and this shrinkage combined with shrink-wrapping of the extendedportions causes some radial compression of the lens in a manner whichtends to move the lens optic relative to the outer ends of the extendedportions in one direction or the other along the axis of the optic. Thefibrosed, leather-like anterior capsule rim prevents anterior movementof the optic and urges the optic rearwardly during fibrosis.Accordingly, fibrosis induced movement of the optic occurs posteriorlyto a distant vision position in which either or both the optic and theinner ends of the extended portions press rearwardly against the elasticposterior capsule of the capsular bag and stretch this posterior capsulerearwardly.

During surgery, the ciliary muscle of the eye is paralyzed with aciliary muscle relaxant, i.e. a cycloplegic, to place the muscle in itsrelaxed state. Following surgery, a ciliary muscle relaxant isperiodically introduced into the eye throughout a post-operativefibrosis and healing period (from two to three weeks) to maintain theciliary muscle in its relaxed state until fibrosis is complete. Thisdrug-induced relaxation of the ciliary muscle prevents contraction ofthe ciliary muscle and immobilizes the capsular bag during fibrosis. Bythis means, the lens optic is fixed during fibrosis in its distantvision position within the eye relative to the retina wherein the lenspresses rearwardly against and thereby posteriorly stretches the elasticposterior capsule of the capsular bag. If the ciliary muscle was notthus maintained in its relaxed state until the completion of fibrosis,the ciliary muscle would undergo essentially normal brain-induced visionaccommodation contraction and relaxation during fibrosis. This ciliarymuscle action during fibrosis would result in improper formation of thepockets in the fibrosis tissue which contain the extended portions ofthe lens. Moreover, ciliary muscle contraction during fibrosis wouldcompress the capsular bag and thereby the lens radially in such a way asto very likely dislocate or decenter the lens from its proper positionin the bag or fix the optic in the near vision position.

When the cycloplegic effect of the ciliary muscle relaxant wears offafter the completion of fibrosis, the ciliary muscle again becomes freeto undergo normal brain-induced contraction and relaxation. Normalbrain-induced contraction of the muscle then compresses the lensradially, relaxes the anterior capsule rim, and increases vitreouspressure in the vitreous chamber of the eye. This normal contraction ofthe ciliary muscle effects anterior accommodation movement of the lensoptic for near vision by the combined action of the increased vitreouspressure, anterior capsule rim relaxation, and the anterior bias of thestretched posterior capsule. Similarly, brain-induced relaxation of theciliary muscle reduces vitreous pressure, relieves radial compression ofthe lens, and stretches the anterior capsule rim to effect posteriormovement of the lens optic for distant vision.

Normal brain-induced relaxation and contraction of the ciliary muscleafter the completion of fibrosis thus causes anterior and posterioraccommodation movement of the lens optic between near and distant visionpositions relative to the retina. During this accommodation movement ofthe optic, the lens extended portions undergo endwise movement withintheir pockets in the fibrous tissue.

The described lens embodiments of the invention conform to one of thefollowing basic lens configurations: (a) a lens configuration, hereafterreferred to as a posteriorly biased lens configuration, in which thehinges of hinged extended portions and the inner ends of resilientlybendable extended portions are located posteriorly of or approximatelyin a plane (tip plane) normal to the optic axis and containing the outertips of the extended portions when the lens occupies its posteriordistant vision position against the posterior capsule of the eye, and(b) a lens configuration, hereafter referred to as an anteriorly biasedlens configuration, in which the hinges of hinged extended portions andthe inner ends of resiliently bendable extended portions are locatedforwardly of the tip plane when the lens occupies its posterior distantvision position against the posterior capsule of the eye. Radialcompression of a posteriorly biased lens by constriction of the ciliarymuscle during accommodation initially urges the lens optic posteriorlyagainst the more dominant anterior forces of the stretched posteriorcapsule and the increasing vitreous pressure which combine to move theoptic forwardly in accommodation against the rearward bias of thecompressing lens until the hinges of hinged extended portions or theinner ends of resiliently bendable extended portions move forwardly ofthe tip plane. Continued radial compression of the lens by ciliarymuscle constriction then aids anterior accommodation movement of thelens. Radial compression of an anteriorly biased lens by constriction ofthe ciliary muscle urges the lens optic anteriorly and thus aids thedominant anterior forces of the stretched posterior capsule and theincreasing vitreous pressure throughout the range of lens accommodation.

According to another important aspect of this invention, the extendedportions of a presently preferred lens embodiment are generally T-shapedhaptics each including a haptic plate and a pair of relatively slenderresiliently flexible fixation fingers at the outer end of the hapticplate. In their normal unstressed state, the two fixation fingers at theouter end of each haptic plate extend laterally outward from oppositeedges of the respective haptic plate in the plane of the plate andsubstantially flush with the radially outer end edge of the plate toform the horizontal “crossbar” of the haptic T-shape. The radially outerend edges of the haptic plates are circularly curved about the centralaxis of the lens optic to substantially equal radii closelyapproximating the radius of the interior perimeter of the capsular bagwhen the ciliary muscle of the eye is relaxed. During implantation ofthe lens in the bag, the inner perimetrical wall of the bag deflects thehaptic fingers generally radially inward from their normal unstressedpositions to arcuate bent configurations in which the radially outeredges of the fingers and the curved outer end edges of the respectivehaptic plates conform approximately to a common circular curvatureclosely approximating the curvature of the inner perimetrical wall ofthe bag. The outer T-ends of the haptics then press lightly against theperimetrical bag wall and are fixated within the bag perimeter duringfibrosis to accurately center the implanted lens in the bag with thelens optic aligned with the anterior capsule opening in the bag.

The haptic plates of certain described lens embodiments are narrower inwidth than the optic diameter and are tapered so as to narrow in widthtoward their outer ends. These relatively narrow plates of the hapticsflex or pivot relatively easily to aid the accommodating action of thelens and form haptic pockets of maximum length in the fibrous tissuebetween the haptic fingers and the optic which maximize theaccommodation movement of the lens optic. The tapered haptics, beingwider adjacent to the optic, can slide radially in the capsular bagpockets during contraction of the of the ciliary muscle to enableforward movement of the optic for vision accommodation.

In some described lens embodiments of the invention, the lens optic andextended portions are molded or otherwise fabricated as an integral onepiece lens structure in which the inner ends of the extended portionsare integrally joined to the optic, and the extended portions are eitherresiliently flexible at each point throughout their length or haveflexible hinges at their inner ends adjacent the optic at which theextended portions are hingable anteriorly and posteriorly relative tothe optic. In other described lens embodiments, the optic and extendedportions are formed separately and have mating hinge portions whichinterengage to pivotally join the optic and extended portions. In someof these described embodiments, the extended portions are T-shapedhaptics formed by molding or otherwise forming the flexible hapticfingers integrally with the haptic plates proper. In other describedinventive embodiments, the extended portions are T-shaped haptics havingT-shaped reinforcing inserts or inlays which both reinforce the hapticplates and provide the haptics with their T-shapes. Still otherdescribed embodiments have reinforcing inserts which reinforce thehaptics, provide the haptics with their T-shapes, and/or provide thehaptics and optic with mating pivotal hinge portions for pivotallyconnecting the haptics to the optic.

According to another important aspect, the invention provides anaccommodating intraocular lens having haptics which are thickened so asto increase in thickness toward their inner ends and have contoured,convexly rounded posterior surfaces adjacent their inner ends. Thesecontoured haptic surfaces and the posterior surface of the lens opticare disposed relative to one another in the axial direction of the opticaxis in such a way that when the intraocular lens occupies its posteriordistant vision in the eye with the ciliary muscle relaxed, the lenscontacts the posterior capsule of the eye in one of the following ways:(a) only the posterior surfaces of the lens haptics contact theposterior capsule, (b) only the posterior surface of the lens opticcontacts the posterior capsule, (c) the posterior surfaces of both thehaptics and optic contact the posterior capsule. In lens configurations(a) and (c) above, the contoured posterior surfaces of the haptics slidealong the posterior capsule during constriction of the ciliary muscle toincrease and enhance anterior accommodating movement of the optic. Inlens configuration (a), the posterior surface of the optic is spacedfrom the posterior capsule to permit laser capsulotomy of the posteriorcapsule without laser damage to the lens optic in the event that theposterior capsule becomes cloudy after implantation of the lens.

A primary and perhaps the most important aspect of the invention isconcerned with increasing the accommodation amplitude of the lens, thatis the distance the lens optic moves along the axis of the eye duringcontraction of the ciliary muscle from its relaxed distant vision stateto its contracted near vision state. This amplitude is commonly measuredand stated in units which are referred to as diopters of accommodation.The maximum accommodation amplitude or diopters of accommodation whichthe eye will accommodate varies from patient to patient. Some patient'seyes, for example, will accommodate on the order of 3.5 diopters ofaccommodation. Other patient's eyes will accommodate a maximum of onlyabout 1.75 diopters of accommodation. Accordingly, it is desireable thatan accommodating intraocular lens according to this invention be capableof at least 3.5 diopters of accommodation so that it can be used on apatient who can accommodate such a lens and thereby eliminate the needfor the patient to wear glasses for near vision.

According to this latter aspect of the invention, the diopters ofaccommodation of the present accommodating intraocular lens areincreased in either or both of the following ways: (a) moving the hingesof lens extended portions or haptics anteriorly relative to theposterior capsule engaging surface(s) of the lens optic in the mannerexplained earlier so as to increase the portion of ciliary musclecontraction over which the resulting muscular compression of the lensproduces an anterior accommodating force on the lens optic, (b)increasing the optical power of the lens, and thereby the amount ofvision accommodation produced by any given accommodation movement of theoptic, by shaping the optic so that most of its optical power is at theposterior side of the optic and the posterior surface of the optic issteeply curved to retain the optic sharply focused on the retina.

Presently preferred accommodating intraocular lenses of the inventionare described. These preferred lenses are anteriorly biased lensincluding generally T-shaped, flexibly hinged haptics and optics whoseposterior portions provide most of the optical power of the optics.These optics cooperate with the anteriorly biased configurations of thelenses to increase accommodation amplitude or diopters of accommodationby both of the ways mentioned above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an anterior face view of an improved posteriorly biasedaccommodating intraocular lens according to the invention having hingedextended portions in the form of T-shaped haptics and showing the lensin its normal unstressed state;

FIG. 2 is an edge view of the improved lens in FIG. 1 looking in thedirection of the arrow 2 in FIG. 1 and showing the hinging action of thelens haptics in broken lines;

FIG. 3 is a section taken through a human eye having the improvedaccommodating intraocular lens of FIGS. 1 and 2 implanted within anatural capsular bag in the eye;

FIG. 4 is an enlarged view taken on line 4—4 in FIG. 3 withportions-broken away for clarity;

FIG. 5 is an enlarged fragmentary section similar to the anteriorportion of FIG. 3 illustrating the initial placement of the lens in theeye;

FIGS. 6-8 are sections similar to FIG. 5 illustrating the normalvision-accommodating action of the accommodating lens;

FIG. 9 is an anterior face view of a modified accommodating intraocularlens according to the invention having extended portions in the form ofresiliently bendable T-shaped haptics;

FIG. 10 is an edge view of the lens in FIG. 9 illustrating theflexibility of the lens haptics;

FIG. 11 is an anterior face view of a modified accommodating intraocularlens according to the invention including three extended portions in theform of hinged T-shaped haptics;

FIG. 12 is an enlarged partial section, similar to the anterior portionof FIG. 3, illustrating a modified posteriorly biased accommodatingintraocular lens of the invention having thickened, curved haptics;

FIG. 13 is a fragmentary sectional view similar to a portion of FIG. 12,showing the lens of FIG. 12 after fibrosis of haptic end portions;

FIG. 14 is a view similar to that of FIG. 11 but showing the lenspositioned for mid-range vision;

FIG. 15 is a view similar to those of FIGS. 13 and 14 but showing thelens positioned to accommodate near vision;

FIG. 16 is a view similar to FIG. 3 but showing an anteriorly biasedaccommodating intraocular lens of the invention in its posterior distantvision position within the eye after completion of fibrosis followingsurgery;

FIG. 17 is an enlargement of the area encircled by the arrow 17—17 inFIG. 16;

FIG. 18 is a further enlarged view of the intraocular lens and naturalcapsular bag of FIG. 17 showing incoming light rays focused on theretina of the eye;

FIGS. 19 and 20 are views similar to the anterior portion of FIG. 18 butillustrating two modified anteriorly biased accommodating intraocularlenses according to the invention in their posterior distant visionpositions within the capsular bag of the eye;

FIG. 21 in an exploded fragmentary perspective view of a modifiedaccommodating intraocular lens according to the invention havingpivotally hinged haptics;

FIG. 22 is a view similar to FIG. 21 but showing a modified haptic hingearrangement including reinforcing hinge inserts or inlays;

FIG. 23 is a view similar to FIG. 22 showing a modified hingearrangement;

FIG. 24 is a perspective view of a further modified accommodatingintraocular lens according to the invention having hinged extendedportions in the form of reinforced plate haptics;

FIG. 25 is a view similar to FIG. 18 but showing a modified, presentlypreferred anteriorly biased accommodating intraocular lens according tothe invention which provides increased accommodation amplitude andincreased diopters of accommodation;

FIG. 26 is an anterior face view of the lens in FIG. 25;

FIG. 27 is an edge view of the lens in FIG. 25; and

FIG. 28 is a view similar to the anterior portion of FIG. 25 showing thepreferred intraocular lens in solid lines in a mid-range position ofaccommodation, in phantom lines in its posterior distant vision positionof accommodation, and in dashed lines in its anterior near visionposition of accommodation.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to these drawings, and first to FIG. 3, there is illustrateda human eye 10 whose natural crystalline lens matrix has been removedfrom the natural lens capsule of the eye through an anterior opening inthe capsule formed by an anterior capsulotomy, in this case a continuoustear circular capsulotomy, or capsulorhexis. As noted earlier, thisnatural lens matrix, which is normally optically clear, often becomescloudy and forms a cataract which is cured by removing the matrix andreplacing it with an artificial intraocular lens.

As mentioned earlier, continuous tear circular capsulotomy, orcapsulorhexis, involves tearing the anterior capsule along a generallycircular tear line in such a way as to form a relatively smooth-edgedcircular opening in the center of the anterior capsule The cataract isremoved from the natural lens capsule through this opening. Aftercompletion of this surgical procedure, the eye includes an opticallyclear anterior cornea 12, an opaque sclera 14 on the inner side of whichis the retina 16 of the eye, an iris 18, a capsular bag 20 behind theiris, and a vitreous cavity 21 behind the capsular bag filled with thegel-like vitreous humor. The capsular bag 20 is the structure of thenatural lens of the eye which remains intact within the eye after thecontinuous tear circular tear capsulorhexis has been performed and thenatural lens matrix has been removed from the natural lens.

The capsular bag 20 includes ark annular anterior capsular remnant orrim 22 and an elastic posterior capsule 24 which are joined along theperimeter of the bag to form an annular crevice-like cul-de-sac 25 (FIG.5) between rim and posterior capsule The capsular rim 22 is the remnantof the anterior capsule of the natural lens which remains aftercapsulorhexis has been performed on the natural lens. This rimcircumferentially surrounds a central, generally round anterior opening26 (capsulotomy) in the capsular bag through which the natural lensmatrix was previously removed from the natural lens. The capsular bag 20is secured about its perimeter to the ciliary muscle 28 of the eye byzonules 30.

Natural accommodation in a normal human eye having a normal humancrystalline lens involves automatic contraction or constriction andrelaxation of the ciliary muscle of the eye by the brain in response tolooking at objects at different distances. Ciliary muscle relaxation,which is the normal state of the muscle, shapes the human crystallinelens for distant vision. Ciliary muscle contraction shapes the humancrystalline lens for near vision. The brain-induced change from distantvision to near vision is referred to as accommodation.

Implanted within the capsular bag 20 of the eye 10 is an accommodatingintraocular lens 32 according to this invention which replaces andperforms the accommodation function of the removed human crystallinelens. The accommodating intraocular lens may be utilized to replaceeither a natural lens which is virtually totally defective, such as acataractous natural lens, or a natural lens that provides satisfactoryvision at one distance without the wearing of glasses but providessatisfactory vision at another distance only when glasses are worn. Forexample, the accommodating intraocular lens of the invention can beutilized to correct refractive errors and restore accommodation forpersons in their mid-40s who require reading glasses or bifocals fornear vision.

Intraocular lens 32 comprises a unitary body which may be formed ofrelatively hard material, relatively soft flexible semi-rigid material,or a combination of both hard and soft materials. Examples of relativelyhard materials which are suitable for the lens body are methylmethacrylate, polysulfones, and other relatively hard biologically inertoptical materials. Examples of suitable relatively soft materials forthe lens body are silicone, hydrogels, thermolabile materials, and otherflexible semi-rigid biologically inert optical materials.

The lens 32 includes a central optic 34 and T-shaped extended portionsor plate haptics 36 extending from diametrically opposite edges of theoptic. These haptics include haptic members or plates 36 a proper havinginner ends joined to the optic and opposite outer free ends and lateralfixation fingers 36 b at their outer ends. The haptic plates 36 a arelongitudinally tapered so as to narrow in width toward their outer endsand may have a width throughout their length less than the diameter ofthe optic 34, and are resiliently flexible for major portions of theirlengths. The haptics 36 are movable anteriorly and posteriorly relativeto the optic 34, that is to say the outer ends of the haptics aremovable anteriorly and posteriorly relative to the optic. The preferredlens embodiment illustrated is constructed of a resilient semi-rigidmaterial and has flexible hinges 38 which join the inner ends of thehaptic plates 36 a to the optic. The haptics are relatively rigid andare flexible about the hinges anteriorly and posteriorly relative to theoptic as shown in FIG. 2. These hinges are formed by grooves 40 whichenter either the anterior or posterior sides and extend across the innerends of the haptic plates 36 a. The haptics 36 are flexible about thehinges 38 in the anterior and posterior directions of the optic. Thelens has a relatively flat unstressed configuration, illustrated in FIG.31 wherein the haptics 36 and their hinges 38 are disposed in a commonplane transverse to the optic axis of the optic 34. Deformation of thelens from this normal unstressed configuration by anterior or posteriordeflection of the haptics about their hinges creates in the hingeselastic strain energy forces which urge the lens to its normalunstressed configuration. The outer end edges 41 of the haptic plates 36a are preferably circularly curved to equal radii about the optic axisof the optic 34, as shown in FIG. 1. In their normal unstressed stateshown in solid lines in FIG. 1, the fingers 36 b of each plate haptic 36extend laterally out from opposite longitudinal edges of the respectivehaptic plate 36 a in the plane of the plate and substantially flush withthe outer end edge 41 of the plate. When unstressed, the fingers 36 bare preferably bowed with a slight radially inward curvature, as shownin solid lines in FIG. 1. As shown in broken lines in FIG. 1, thefingers 36 b are laterally resiliently flexible radially of the hapticplates 36 a to their broken line positions of FIG. 1 in which theradially outer edges of the fingers and the end edges 41 of the hapticplates 36 a conform substantially to a common circle centered on theaxis of the optic 34.

The accommodating intraocular lens 32 is implanted within the capsularbag 20 of the eye 10 in the position shown in FIGS. 4 and 5. Whenimplanting the lens in the eye, the ciliary muscle 28 of the eye isparalyzed in its relaxed state, shown in FIG. 5, in which this musclestretches the capsular bag 20 to its maximum diameter. The lens isinserted into the bag through the anterior capsule opening 26 and issized in length, endwise of the haptics 36, for placement of the lens inthe position shown in FIGS. 4 and 5. In this position, the lens optic 34is aligned with anterior opening 26 in the bag, as shown in FIG. 4. Theposterior side of the lens faces the elastic posterior capsule 24 of thecapsular bag, and the posterior side of the lens optic 34 is disposed inclose proximity to or contacts the posterior capsule. The radially outerT-ends of the lens haptics 36 are positioned within the cul-de-sac 25 ofthe capsular bag with the outer end edges 41 of the haptic plates 36 aand the haptic fingers 36 b in close proximity to or seating lightlyagainst the capsular bag cul-de-sac wall. This cul-de-sac wall deflectsthe haptic fingers inwardly to the positions shown in broken lines inFIG. 4 (which approximate the broken line finger positions shown in FIG.1). In these deflected positions, the end edges 41 of the haptic platesand the haptic fingers 36 b conform closely to the curvature of thecul-de-sac wall to accurately center the lens in the capsular bag. Thelens is thus sized and shaped so that when the ciliary muscle 28 isparalyzed in its relaxed state, the lens fits in the capsular bag 20with a sufficiently close fit to accurately align the lens optic 34 withthe anterior capsule opening 26 in the bag without significantlydeforming the bag.

The actual dimensions of an intraocular lens according to this inventionwill be determined by each patient's ocular dimensions. Following arethe dimensions of a typical accommodating intraocular lens according tothe invention:

Diameter of optic 34 4.50 mm Inner end width of haptic plates 36a 1.5 mmOuter end width of haptic plates 36a 1.3 mm Outer end radius of hapticplates 36a 5.25 mm Haptic finger thickness 0.12 mm Distance betweenunstressed haptic finger tips 4.5 mm Longitudinal distance betweenunstressed haptic 11.5 mm finger tips

During a post-operative fibrosis and healing period on the order of twoto three weeks following surgical implantation of the lens 32 in thecapsular bag 20, epithelial cells under the anterior capsular rim 22 ofthe bag cause fusion of the rim to the posterior capsule 24 by fibrosis.This fibrosis occurs around the lens haptics 36 in such a way that thehaptics are “shrink-wrapped” by the capsular bag 20, and the hapticsform pockets 42 in the fibrosed material 43. These pockets cooperatewith the lens haptics to position and center the lens in the eye. Inorder to insure proper formation of the haptic pockets 42 and preventdislocation of the lens by ciliary muscle contraction during fibrosis,sufficient time must be allowed for fibrosis to occur to completionwithout contraction of the ciliary muscle 28 from its relaxed state ofFIG. 5. This is accomplished by introducing a ciliary muscle relaxant(cycloplegic) into the eye before surgery to dilate the pupil andparalyze the ciliary muscle in its relaxed state and having the patientperiodically administer cycloplegic drops into the eye during apost-operative period of sufficient duration (two to five weeks) topermit fibrosis to proceed to completion without contraction of theciliary muscle. The cycloplegic maintains the ciliary muscle 28 in itsrelaxed state in which the capsular bag 20 is stretched to its maximumdiameter (FIG. 5) and immobilized, and the anterior capsular rim 22 isstretched to a taut trampoline-like condition or position. The rimfibroses from this taut condition. The cycloplegic passes through thecornea of the eye into the fluid within the eye and then enters theciliary muscle from this fluid. While other cycloplegics may be used,atropine is the preferred cycloplegic because of its prolongedparalyzing effect compared to other cycloplegics. One drop of atropine,for example, may last for two weeks. However, to be on the safe side,patients may be advised to place one drop of atropine in the eye everyday during the fibrosis period.

The capsular rim 22 shrinks during fibrosis and thereby shrinks thecapsular bag 20 slightly in its radial direction. This shrinkagecombines with shrink wrapping of the lens haptics 36 produces someopposing endwise compression of the lens which tends to buckle or flexthe lens at its hinges 38 and thereby move the lens optic 34 along theaxis of the eye. Unless restrained, this flexing of the lens might occureither forwardly or rearwardly. The taut anterior capsular rim 22 pushesrearwardly against and thereby prevents forward flexing of the lens.This fibrosis-induced compression of the lens is not sufficient tointerfere with proper formation of the haptic pockets in the fibrosedtissue or cause dislocation of the lens. Accordingly endwise compressionof the lens by fibrosis aided by the rearward thrust of the tautcapsular rim against the lens haptics 36 causes rearward flexing of thelens from its initial position of FIG. 5 to its position of FIG. 6. Thelens haptics 36 are made sufficiently rigid that they will not buckleunder the forces of fibrosis. At the conclusion of fibrosis, the lensoccupies its posterior position of FIG. 6 wherein the lens pressesrearwardly against the elastic posterior capsule 24 and stretches thiscapsule rearwardly. The posterior capsule then exerts a forward elasticbias force on the lens. This posterior position of the lens is itsdistant vision position.

Natural accommodation in a normal human eye involves shaping of thenatural crystalline lens by automatic contraction and relaxation of theciliary muscle of the eye by the brain to focus the eye at differentdistances. Ciliary muscle relaxation shapes the natural lens for distantvision. Ciliary muscle contraction shapes the natural lens for nearvision.

The accommodating intraocular lens 32 is uniquely constructed to utilizethis same ciliary muscle action, the fibrosed capsular rim 22, theelastic posterior capsule 24, and the vitreous pressure within thevitreous cavity 21 to effect accommodation movement of the lens optic 34along the optic axis of the eye between its distant vision position ofFIG. 6 to its near vision position of FIG. 8. Thus, when looking at adistant scene, the brain relaxes the ciliary muscles 28. Relaxation ofthe ciliary muscle stretches the capsular bag 20 to its maximum diameterand its fibrosed anterior rim 22 to the taut condition or positiondiscussed above. The taut rim deflects the lens rearwardly to itsposterior distant/vision position of FIG. 8 in which the elasticposterior capsule 24 is stretched rearwardly relative to the generalplane of the fibrosed haptic end portions, by the lens and therebyexerts a forward bias force on the lens. When locking at a near scene,such as a book when reading, the brain constricts or contracts theciliary muscle. This ciliary muscle contraction has the three-foldeffect of increasing the vitreous cavity pressure, relaxing the capsularbag 20 and particularly its fibrosed capsular rim 22, and exertingopposing endwise compression forces on the ends of the lens haptics 36with resultant endwise compression of the lens. Relaxation of thecapsular rim permits the rim to flex forwardly and thereby enables thecombined forward bias force exerted on the lens by the rearwardlystretched posterior capsule and the increased vitreous cavity pressureto push the lens forwardly relative to the general plane of the fibrosedhaptic end portions, in an initial accommodation movement from theposition of FIG. 6 to the intermediate accommodation position of FIG. 7.

In this intermediate accommodation position, the lens is substantiallyflat, and the ends of the lens haptics and their hinges 38 are disposedsubstantially in a common plane normal to the axis of the eye. Prior toaccommodation, the lens arches rearwardly so that endwise compression ofthe lens by ciliary muscle contraction tends to produce a rearwardbuckling force on the lens. However, the increased vitreous cavitypressure and the forward bias force of the stretched posterior capsuleare sufficient to overcome this opposing rearward buckling force andeffect forward accommodation movement of the lens to and at least justslightly beyond the intermediate position of FIG. 7. At this point,endwise compression of the lens by the contracted ciliary muscleproduces a forward flexing force on the lens which effects finalaccommodation of the lens beyond the intermediate position of FIG. 7 tothe near vision position of FIG. 8. Subsequent brain-induced relaxationof the ciliary muscle 28 in response to looking at a distant scenereduces the vitreous cavity pressure, stretches the capsular bag 20 toits maximum diameter, and restores the anterior capsular rim 22 to itstaut trampoline-like condition to effect return of the lens to itsdistant viewing position of FIG. 8. During accommodation, the lens optic34 moves along the axis of the eye. The effective power of the optic isselected by the brain to sharply focus incoming light by moving theoptic along the axis of the eye by contraction and relaxation of theciliary muscle.

The lens haptics 38 flex at their hinges 38 with respect to the lensoptic 34 during accommodation. Any elastic strain energy forcesdeveloped in the hinges during this flexing produces additional anteriorand/or posterior forces on the lens. For example, assume that the lensis relatively flat, i.e., that the lens haptics 36 lie in a common planeas shown in FIG. 1, in the normal unstressed state of the lens. In thiscase, posterior deflection of the lens from its position of FIG. 1 toits distant vision position of FIG. 6 creates elastic strain energyforces in the hinges 38 which urge the lens forwardly back to itsunstressed position of FIG. 1 and thus aid the above discussed initialaccommodation of the lens in response to contraction of the ciliarymuscle. Final accommodation flexing of the lens from its intermediateposition of FIG. 7 to its near vision position of FIG. 8 creates elasticstrain energy forces in the hinges 38 which urge the lens rearwardlytoward its unstressed position and thus aid initial return of the lensfrom its near vision position to its distant vision position in responseto relaxation of the ciliary muscle. The lens may be designed to assumesome other normal unstressed position, of course, in which case anyelastic strain energy forces created in the lens during flexing of thehaptics will aid, resist, or both aid and resist accommodation of thelens to its near vision position and return of the lens to its distantvision position depending upon the unstressed position of the lens.

During accommodation, the lens haptic plates 36 a slide endwise in theirfibrosed tissue pockets 42. As shown best in FIGS. 1, 2 and 4, thehaptics are tapered endwise in width and thickness to enable the hapticsto move freely in the pockets. The lens optic 34 moves forwardly towardand rearwardly away from the anterior capsular rim 22. The diameter ofthe optic is made as large as possible to maximize its optical imagingefficiency. The optic is preferably but not necessarily made smallerthan the diameter of the anterior capsule opening 26 to permitaccommodation movement of the optic into and from the opening withoutinterference by the capsular rim 22 in order to maximize theaccommodation range.

The modified accommodating intraocular lens 100 shown in FIGS. 9 and 10is identical to the lens 32 shown in FIGS. 1-8 except as noted below.Thus the modified lens has an optic 102 and generally T-shaped haptics104 extending radially out from diametrically opposite edges of theoptic. These haptics include longitudinally tapered haptic plates 106and flexible haptic fingers 108 at the outer ends of these platesextending laterally out from the longitudinal edges of the plates. Themodified lens 100 differs from the lens 32 only in that the haptichinges 38 and hinge grooves 40 of the lens 32 are omitted in themodified lens 100, and the haptic plates 108 of the modified lens aremade resiliently flexible or bendable throughout their length, asindicated in broken lines in FIG. 10. The modified lens is implanted ina capsular bag of a human eye and provides vision accommodation inresponse to ciliary muscle contraction and relaxation in the same manneras described in connection with the lens 32.

The accommodating intraocular lens 110 of FIG. 11 differs from theearlier-described lenses, in that it embodies an optic 112 from whichextend three haptics 36 a extending radially outward. Haptic 36 aincludes a longitudinally tapered haptic plate 114 and flexible hapticfingers 36 b. Although three haptics are shown, it will be understoodthat four or even more haptics can be provided. Like the lenses earlierdescribed, the lens 110 is implanted in the capsular bag of a patient'seye and provides vision accommodation in response to ciliary musclecontract in and relaxation. The multiple haptics of the lens 110, whichcan be three or more in number, are equally spaced about the axis of theoptic 112 and provide improved centration of the lens in the capsularbag of the eye with the lens optics 112 aligned with the anterioropening in the bag.

The accommodating intraocular lens 200 of FIGS. 12-15 is identical tothe lens of FIGS. 1-8 except that the plate portions of the T-shapedextend portions or plate haptics 202 of lens 200 increase in thicknessfrom their outer tip ends toward their inner junctures with the optic204. The thickened portions of the haptics have convexly curvedposterior surfaces 206 which curve rearwardly beyond the posteriorsurface of the optic 204 and away from the anterior surfaces of thehaptics for major portions of the haptic lengths from the outer hapticends toward the inner haptic ends. The posterior haptic surfaces thencurve forwardly toward the anterior haptic surfaces at the inner hapticends to form thinned flexible hinge portions 208 pivotally joining thehaptics to the optic.

The lens 200 is implanted within the capsular bag of a patient's eye inthe initial position of FIG. 12, after which fibrosis is permitted tooccur about the lens haptics 202 with the ciliary muscle paralyzed inits related state, all in the same manner as explained earlier inconnection with FIGS. 1-8. As in FIGS. 1-8, the lens is urged rearwardlytoward the posterior capsule 24 of the capsular bag 20 during fibrosisto the posterior distant vision position of FIG. 13. In this posteriorposition, the rearwardly projecting posterior surfaces 206 of thehaptics contact the posterior capsule 24 and space the posterior surfaceof the optic 204 from the capsule.

Contraction of the ciliary muscle during normal vision accommodationafter fibrosis is complete increases vitreous pressure and compressesthe lens 200 radially or endwise. The increasing vitreous pressureproduced by such muscle contraction together with the rearwardlystretched posterior capsule 24 exert anterior forces, indicated by thearrows V in FIG. 13, on the rearwardly projecting thickened haptics 202.These forces move the lens optic 204 anteriorly for accommodation inmuch the same manner as explained above in connection with FIGS. 1-8except for the following haptic movement. During accommodation of lens200, the arcuate posterior surfaces 206 of the thickened haptics 202slide inwardly across posterior capsule 24, and the inner ends of thehaptics rotate forwardly while their outer ends remain in contact withthe posterior capsule, as shown in FIGS. 13-16. This increases theanterior accommodation movement of the optic from its posterior distantvision position of FIG. 13, through its midrange position of FIG. 14, toits near vision position of FIG. 15. When the ciliary muscle relaxes, itradially stretches the capsular bag of the eye and thereby pullsradially out on the encapsulated T-shaped ends of the lens haptics 202to aid return of the lens to its posterior distant vision position.

Thickening the lens haptics 202 in the manner shown and describedprovides two advantages in addition to the above mentioned advantage ofincreasing the accommodation amplitude of the lens optic 204. One ofthese additional advantages resides in the fact that rearwardlythickening the haptics increases the spacing, along the axis of theoptic, between the haptic hinges 208 and the posterior portion of thelens which contacts the posterior capsule 24, in this case the posteriorhaptic surfaces 206. Increasing this spacing has the effect of shiftingthe hinges forwardly relative to the posterior capsule 24 and henceforwardly relative to the plane P in FIG. 13 (tip plane) passing throughthe outer tips of the lens haptics 202 normal to the optic axis when thelens occupies its posterior distant vision position. This forward shiftof the hinges relative to the haptic tip plane P, in turn, increases theportion of ciliary muscle contracting during accommodation over whichthe haptics hinges are located forwardly of the tip plane and hence theportion of such muscle contraction over which compression of the lens200 by such muscle contraction produces an anterior force on the lensoptic which aids vitreous pressure in moving the optic forwardly inaccommodation and thereby further increases the accommodation amplitudeof the lens.

The second additional advantage of thickening the lens haptics 202 inthe manner illustrated (i.e. so that they protrude rearwardly beyond theposterior surface of the lens optic 204) spaces this posterior opticsurface from the posterior capsule 24, as shown in FIGS. 13-15. Thisspacing permits a laser capsulotomy to be performed on the posteriorcapsule, if it becomes cloudy, by sharply focusing a YAG laser beam onthe capsule through the cornea of the eye and the lens optic 204 withoutthe danger of contacting the intense laser beam focus point with theposterior surface of the optic with which would pit or otherwise degradethis optic surface.

It is worthwhile to recall here that accommodating intraocular lenses ofthe invention conform to one or the other of the following basic lensconfigurations: (a) a posteriorly biased lens configuration in which thehinges or inner ends of the extended portions or haptics of the lens arelocated posteriorly of or approximately in a tip plane passing throughthe outer tips of the extended portions or haptics normal to the opticaxis when the lens occupies its posterior distant vision position, (b)an anteriorly biased lens configuration in which the hinges or inner endof the extended portions or haptics are located forwardly of the tipplane when the lens occupies its posterior distant vision position. Theaccommodating intraocular lenses described to this point are posteriorlybiased lenses.

In this regard, it will be seen that the lenses 32, 200 are sized andshaped so that when they assume or occupy their distant visionconfigurations (i.e. the configurations which the lenses assume oroccupy in their posterior distant vision positions of FIGS. 6 and 13),their haptic hinges 38, 208 are located rearwardly of a plane P (tipplane) passing through the outer tips of the lens haptics 36, 202 normalto the optical axis of the lens optics 34, 204. This relationship isattained by sizing and shaping each lens in such a way that the distanceor spacing along the optical axis of its optic between the posteriorportion(s) of the lens which contact(s) the posterior capsule 24 of thepatient's eye (i.e. the posterior surface of the lens optic 34 in FIG. 6and the posterior surfaces 206 of the thickened lens haptics 202 in FIG.13) and the lens hinges 38, 208 is less than the distance or spacingalong the axis of the eye between the portion(s) of the posteriorcapsule contacted by the lens and a plane (tip plane P) passing throughthe annular haptic-tip-receiving sulcus of the capsular bag 20 normal tothe axis of the eye.

It is evident from FIGS. 6 and 13 that radial or endwise compression ofposteriorly biased lenses 32, 200 by contraction of the ciliary muscleduring accommodation initially urges the lens optics 34, 204 rearwardlyin opposition to the combined anterior forces of the stretched posteriorcapsule and the increasing vitreous pressure. These anterior forces aredominant and move the lens optics anteriorly against the opposingposterior bias forces produced by ciliary muscle compression of thelenses to effect vision accommodation, as explained earlier. Initialmovement of the haptic hinges 38, 208 during this accommodation occursforwardly to the mid-range lens positions of FIGS. 7, 14 in which thehinges are located approximately in their tip planes P. Continuedcompression of the lenses by ciliary muscle contraction at this pointmoves the hinges forwardly of their tip planes, whereupon the biasforces produced on the lens optics 32, 204 by such lens compressionreverse to become anterior forces which aid further anterioraccommodation movement of the lenses by vitreous pressure to their nearvision positions of FIGS. 8, 12. Relaxation of the ciliary musclereduces vitreous pressure and stretches the capsular bags radially whichpulls the encapsulated T-shaped outer ends of the haptics radiallyoutward to aid return of the lenses to their posterior distant visionpositions of FIGS. 6, 13.

Referring now to FIGS. 16-18, there is illustrated an anteriorly biasedaccommodating intraocular lens 300 according to the invention in itsposterior distant vision position within the capsular bag 20 of apatient's eye. Lens 300 is identical to lens 200 except in the followingrespects. The anterior surfaces 302 of the thickened T-shaped extendedportions or plate haptics 304 of lens 300 are flush with the anteriorsurface of the lens optic 306. The posterior haptic surfaces 308 inclinerearwardly away from the anterior haptic surfaces 302 from the outerhaptic tips toward their inner junctions with the optic 306 and thenforwardly toward the anterior haptic surfaces to define, with theperipheral edge of the optic, posterior V-shaped notches which formthinned flexible hinges 310 at the inner haptic ends. The optic 306 hasa convexly rounded posterior surface 312.

Lens 300 is implanted in the capsular bag 20 in the same way as theearlier described lenses and is subjected to the same ciliary musclecontraction and relaxation as the earlier described lenses during normalvision accommodation following completion of fibrosis. Lens 300 is sosized and shaped that the posterior surfaces 308 of its haptics 304 andthe posterior surface 312 of its optic 306 contact the posterior capsule24 of the bag 20. When the lens 300 occupies its posterior distantvision configuration of FIGS. 16-18 which it assumes in its posteriordistant vision position shown in the latter figures, its hinges 310 arelocated a small distance forwardly of the haptic tip plane P of thelens, i.e. a plane passing through the outer tips of the haptics 304 andthe annular haptic-tip-receiving sulcus of the capsular bag 20 normal tothe axis of the lens and the eye. Accordingly, during ciliary musclecontraction in the course of normal accommodation, end to end or radialcompression of the lens 300 and vitreous pressure both exert anterioraccommodation forces on the lens optic 306 throughout its fullaccommodation range. This combined action of the two forces increasesthe accommodation amplitude and hence diopters of accommodation of thelens.

FIGS. 19 and 20 illustrates two modified anterior biased accommodatingintraocular lenses 300 a and 300 b according to the invention implantedwithin a capsular bag 20 of a patient's eye. These modified anteriorbiased lenses are identical to and undergo accommodation in much thesame manner as the anterior biased lens of FIGS. 16-18 with thefollowing exceptions. In lens 300 a, only the posterior surfaces 304 aof the T-shaped extended portions or plate haptics 302 a of the lenscontact the posterior capsule 24 of the capsular bag. Accordingly,vitreous pressure acts only on these haptics during accommodation, andthe lens optic is immune to laser damage during laser capsulotomy of theposterior capsule, as in the lens 200 of FIGS. 12-15. The posteriorsurface 312 a of the lens optic 306 a is spaced from the posteriorcapsule. In lens 300 b, only the posterior surface 312 b of the lensoptic 306 b contacts the posterior capsule 24 of the capsular bag. Theposterior surfaces 304 b of the T-shaped plate haptics 302 b of the lensare spaced from the posterior capsule. Accordingly, duringaccommodation, vitreous pressure acts only on the posterior surface ofthe optic.

All of the accommodating intraocular lenses of the invention describedto this point, except the lens of FIGS. 9 and 10, have hinged extendedportions in the form of haptics with resiliently flexible haptic hinges.FIGS. 21-23 illustrate modified lenses having extended portions in theform of pivotally hinged haptics. The lens 400 a of FIG. 21 includes acentral optic 402 a and T-shaped plate haptics 404 a (only one shown)spaced circumferentially about and joined by pivotal hinges 406 a to theedge of the optic. Each haptic hinge 406 a comprises mating hingeportions 408 a, 410 a on the respective haptic and the optic whichpivotally interengage to pivotally connect the haptics to the optic foranterior and posterior movement of the haptics relative to the optic. InFIG. 21, each haptic hinge portion 408 a comprises a tongue 412 aintegrally molded or otherwise formed along the inner end of andcoplanar with the respective haptic plate portion 414 a and having agenerally cylindrical head 416 along the inner edge of the tongue. Eachoptic hinge portion 410 a includes a hinge groove or channel 418 a alongthe edge of the optic 402 a which opens laterally outward toward thehaptic. Each hinge groove 418 a is cylidrically curved, undercut andsized in transverse cross-section to pivotally receive the bead 416 a onthe adjacent haptic tongue 412 a in such a way that the head iscaptivated in the groove, and the respective haptic 404 a is pivotallymovable through a certain angle anteriorly and posteriorly relative tothe optic.

The optic 402 a and each haptic plate 414 a may be molded or otherwisefabricated from any suitable intraocular lens material including theintraocular lens materials listed earlier. All of these materials havesuitable optical and other qualities for an intraocular lens. Some ofthese materials are sufficiently hard or firm to permit each haptichinge tongue 412 a to be molded or otherwise formed integrally with itshaptic plate 414 a and each haptic hinge groove 418 a to be molded orotherwise formed directly in the material of the lens optic 402 a, as inthe lens 400 a of FIG. 21.

The modified accommodating intraocular lenses 400 b of FIG. 22 and 400cof FIG. 23 are essentially identical to less 400 a of FIG. 21 except inthe following respects. The optics and haptic plates of lenses 400 b,400 c are made from a material which is not sufficiently firm or hard touse for hinge purposes, and their hinge formations are separatelyfabricated from intraocular lens materials which are suitably hard orfirm for hinge purposes and which form reinforcing hinge inserts orinlays that are molded within the optics and the haptic plates of thelenses 400 b, 400 c. For this reason, the parts of lenses 400 b, 400 care designated by the same reference numerals as their correspondingparts of lens 400 a but with the subscripts b or c, as the case may be.

With the foregoing in mind, each extended portion or haptic 404 b oflens 400 b comprises an elongate hinge plate 420 b which is encapsulatedwithin, extends edgewise through, and forms a reinforcing insert orinlay within the respective haptic plate 414 b. At the inner end of thishinge plate is a cross-bar 422 b which projects edgewise beyond theinner end of the haptic plate 414 b to form the tongue 412 b of therespective haptic hinge position 408 b. At the outer end of each hingeplate 420 b are flexible fingers 424 b which provide the lens haptic 404b with its T-shape. Each optic hinge portion 410 b comprises a bar whichis encapsulated within and forms a reinforcing insert or inlay in theedge of the lens optic 402 b. Along the outer edge of this bar is thehinge groove or channel 418 b which pivotally receives the cylindricalbead 416 b along the adjacent hinge tongue 412 b.

The modified lens 400 c of FIG. 23 is identical to lens 400 b exceptthat the inner end of each haptic plate 414 c of lens 400 c extendsendwise beyond the inner cross bar 422 c of the reinforcing hinge plate408 b which forms the respective haptic hinge portion 408 c of lens 400c. This extending inner end of each haptic plate 414 c has acylindrically rounded surface and a central slot 426 c. Each optic hingeportion 410 c comprises a hinge bar 428 c encapsulated in the edge ofthe lens optic 402 c and having a central rounded hinge projection 420c. This hinge projection fits rotatably within the notch 426 c of theadjacent haptic hinge portion 408 c and is pivotally connected to thehaptic hinge portion, to form the respective haptic hinge 406 c, by ahinge pin 432 c which extends through aligned bores in the haptic hingeportion and the optic hinge projection.

The modified accommodating intraocular lens 500 of FIG. 24 has extendedportions in the form of flexibility hinged plate haptics 501 includingflexible haptic plate portions 502 integral with and extending radiallyout from edges of the lens optic 504, the plate haptics being generallyresiliently flexible throughout at least a major portion of theirlengths. These haptic plate portions have cutouts 506 including taperedlongitudinal outer ends 508 which widen toward and open through theouter ends of the haptics and arcuate inner end slots 510 which extendlaterally toward the longitudinal edges of the haptics to form flexiblehaptic hinges 512 between the outer ends of the slots and thelongitudinal edges of the haptic portions. Haptics 501 are reinforcedlongitudinally outward of the hinges 512 by T-shaped inserts 514 havingtapered inner end portions 516 fixed within the tapered outer ends 508of the haptic cutouts 506. Lens 500 is implanted in the eye in the samemanner as the earlier described lens and flexes at its flexible hinges512 during contraction and relaxation of the ciliary muscle to effectvision accommodation.

FIGS. 25-28 illustrate a presently preferred accommodating intraocularlens 600 according to the invention implanted within a capsular bag 20of a patient's eye. This preferred lens is an anteriorly biased lenswith flexibly hinged extended portions in the form of T-shaped hapticswhich achieves increased accommodation amplitude and increased dropletsof accommodation by the combined action of (a) its anteriorly biassedconfiguration which increases accommodation amplitude and increaseddiopters of accommodation in the manner explained earlier, and (b)increased power of its optic which increases the amount of accommodationproduced by any given amount of accommodation movement of the lens opticor, conversely reduces the accommodation movement of the optic requiredto produce any given amount of accommodation.

Lens 600 comprises a one piece lens structure having a central optic 602and flexibly hinged extended portions 604 in the form of T-shaped platehaptics extending generally radially out from the optic. Each platehaptic 604 is longitudinally tapered in width and thickness so as towiden in width and increase in thickness toward its inner end. Eachplate haptic includes an inner plate portion 606 which is integrallyjoined to an edge of the optic 602 and inclines anteriorly relative tothe optic toward its outer end, an outer plate portion 608 joined to theouter end of the inner plate portion, and a V-groove 610 entering theposterior side of the haptic at the juncture of these plate portions soas to form at this juncture a flexible hinge 612. The outer plateportion 608 is pivotally movable at this hinge anteriorly andposteriorly relative to the inner plate portion 606 and the optic 602.The lens structure including its optic 602 and haptic plate portions606, 608 is molded or otherwise formed as a unitary lens structure froma lens material mentioned earlier and has T-shaped inserts 614 fixed inthe outer ends of the outer haptic plate portions 608. These insertsprovide the lens extended portions or haptics 604 with their T-shape andmay be utilized to reinforce the outer haptic plate portions 608 ifnecessary.

Lens 600 is implanted in the capsular bag 20 of the eye with the ciliarymuscle of the eye paralyzed in its relaxed state and maintained in thisparalyzed state until the completion of fibrosis, all in the same manneras explained earlier. During this fibrosis, the lens optic 602 is urgedposteriorly to its distant vision position shown in solid lines in FIG.25 and dashed lines in FIG. 28 wherein the posterior surface of theoptic presses rearwardly against the posterior capsule 24 of thecapsular bag and stretches this posterior capsule rearwardly. Theconfiguration which the lens 600 assumes or occupies in this posteriordistant vision position is its posterior distant vision configuration.Ciliary muscle contraction during normal vision accommodation followingcompletion of fibrosis increases vitreous pressure and compresses thelens radially or endwise to effect anterior accommodation movement ofthe lens optic 602 in the same manner as explained earlier.

As mentioned above, lens 600 is an anteriorly biased lens. In thisregard, it will be observed in FIGS. 25 and 28 that when the lensoccupies its posterior distant vision position, its haptic hinges 612are located forwardly of a tip plane P_(T) passing through the outertips of the lens haptics 604 normal to the axis of the lens optic 602and the eye. Accordingly, compression of the lens by ciliary musclecontraction during normal vision accommodation is effective to producean anterior accommodation force on the optic throughout its entireaccommodation range from its posterior distant vision through itsmid-range position (solid lines in FIG. 28) to its anterior near visionposition (phantom lines in FIG. 28). Compression of the lens by ciliarymuscle contraction thereby aids the anterior vitreous pressure force onthe optic throughout its entire accommodation range and therebyincreases the accommodate amplitude and diopters of accommodation of thelenses, as explained earlier.

An important feature of lens 600 resides in the fact that its optic 602has increased optical or dioptic power which aids the anterior biasedconfiguration of the lens to further increase accommodation amplitudeand diopters of accommodation. To this end, the anterior face 616 of theoptics is relatively flat or just slightly convex while the posteriorface 618 of the optic has a relatively steep convex curvature such thatthe optic has a generally planoconvex shape. This optic shape locatesmost or all of the optical power of the optic at the posterior side ofthe optic. Increasing the power of the lens optic in this way decreasesthe distance through which the optic must move to produce any givenamount of vision accommodation and, conversely, increases the amount ofvision accommodation produced by any given accommodation movement of theoptic and thereby increases the maximum accommodation amplitude anddiopters of accommodation of the lens.

Increasing the power of an intraocular lens optic at the posterior sideof the optic, as in FIGS. 25-28, shifts the optical plane of the optic(i.e. plane from which the focal point of the optic originates)rearwardly toward the retina 16 of the eye. For example, the opticalplane P_(O) of lens optic 602 is located at the approximate positionshown in FIG. 25 which is rearwardly of the optical plane position (notshown) of a symmetrical biconvex optic of the same center thicknessmeasured along the axis of the optic but having anterior and posteriorsurfaces of equal curvature). This rearward shaft of the optical planeof the optic toward the retina must be compensated for by increasing thedioptic power of the optic in order to sharply focus incoming light rayson the retina. The required increase in the power of optic 602 isaccomplished by appropriately shaping the steep convex curvature of theposterior surface 618 of the optic.

At this point, refer again to FIGS. 16-20 in which it will be observedthat the lens illustrated in each of these figures includes a centraloptic whose posterior surface has a greater convex curvature than itsanterior surface. Accordingly, the lens optic illustrated in each of theFIGS. 16-20 is a “rear power” optic most of whose optical power isprovided by the posterior surface of the optic. Accordingly, the lensesof FIGS. 16-20 provide increased accommodation amplitude and diopters ofaccommodation in essentially the same manner as explained above inconnection with FIGS. 25-28.

The inventor claims:
 1. An accommodating intraocular lens forimplantation into a generally circular inner surface of an eye,comprising: (a) an optic; (b) at least two haptics spaced apart fromeach other and extending generally radially away from the optic, adaptedto engage the generally circular inner surface of the eye for holdingthe lens in the eye; (c) each of the haptics including an outer portionwith a surface adapted to engage the generally circular inner surface ofthe eye, at least part of said outer surface extending beyond thediameter of the generally circular inner surface of the eye, when saidouter portions is in its unstressed state, said outer portion beingflexible and not conforming to the generally circular inner surface ofthe eye until subjected to compressive forces, so that the outer surfacewill conform generally to the shape of the inner surface of the eye whensubjected to said compression forces upon implantation; and (d) thehaptics being flexible along at least a portion of their respectivelengths to move the optic anteriorly and/or posteriorly in response toforces imparted to the lens through contraction and expansion of thegenerally circular inner surface of the eye.
 2. The lens of claim 1,wherein the optic is circular.
 3. The lens of claim 1, wherein thehaptics are connected to and extend from an outer edge of the optic. 4.The lens of claim 1, wherein the lens is formed of a single piece ofmaterial.
 5. The lens of claim 1, wherein two haptics extend fromopposite sides of the optic.
 6. The lens of claim 1, wherein threehaptics are spaced apart an equal distance from each other around theoptic.
 7. The lens of claim 1, wherein the haptics include opposedlongitudinal edges that taper inwardly as they extend from the optic. 8.The lens of claim 1, wherein the haptics include upper and lower surfacethat taper inwardly as they extend from the optic.
 9. The lens of claim1, wherein the haptics include a lower surface extending rearwardlybeyond a horizontal plane of a posterior surface of the optic.
 10. Thelens of claim 1, wherein at least a portion of a haptic upper surfaceextends forwardly beyond a horizontal plane of a anterior surface of theoptic.
 11. The lens of claim 1, wherein the haptics and optic arepositioned in a normally uniplanar alignment when unstressed.
 12. Thelens of claim 1, wherein each haptic includes an outer end and saidouter portion includes a pair of fingers extending from the outer end.13. The lens of claim 12, wherein the fingers are relatively straight intheir unstressed state.
 14. The lens of claim 12, wherein the fingersare curved inwardly in their unstressed state.
 15. The lens of claim 12,wherein the fingers are formed integrally with each haptic.
 16. The lensof claim 12, wherein the fingers are attached to the outer end of eachhaptic.
 17. The lens of claim 12, wherein the fingers extend fromopposite sides of each haptic.
 18. The lens of claim 12, wherein thefingers include an enlarged portion adapted to be encapsulated by theinner surface of the eye so as to hold the haptics in place relative tothe inner surface of the eye when the inner surface of the eye expandsand contracts.
 19. The lens of claim 18, wherein the enlarged portion isa knob.
 20. The lens of claim 1, wherein each haptic includes at leastone hinge adapted to allow the optic to move posteriorly when the innersurface of the eye expands and to move anteriorly when the inner surfacecontracts.
 21. The lens of claim 20, wherein the hinge has an elasticmemory operable to bias the hinge back to its normally unstressedposition following contraction or expansion of the inner surface of theeye.
 22. The lens of claim 21, wherein the hinge is a groove extendingacross at least one side of the haptic.
 23. An accommodating intraocularlens for implantation into a generally circular inner surface of an eye,comprising: (a) an optic; (b) at least two haptics spaced apart fromeach other and extending generally radially away from the optic, adaptedto engage the generally circular inner surface of the eye for holdingthe lens in the eye; (c) each of the haptics including an other portionwith a surface shaped to engage the generally circular inner surface ofthe eye, at least part of said outer surface extending beyond thediameter of the generally circular inner surface of the eye, when saidouter portion is in its unstressed state, said outer portion beingflexible and not conforming to the generally circular inner surface ofthe eye until subjected to compressive forces, so that the outer surfacewill conform generally to the shape of the inner surface of the eye whensubjected to said compression forces upon implantation; and (d) each ofthe haptics include including at least one hinge adapted to move theoptic anteriorly and/or posteriorly in response to forces imparted tothe lens through contraction and expansion of the generally circularinner surface of the eye.
 24. The lens of claim 23, wherein the hingehas an elastic memory operable to bias the hinge back to its normallyunstressed position following contraction or expansion of the innersurface of the eye.
 25. The lens of claim 23, wherein the hinge is agroove extending across at least one side of the haptic.
 26. The lens ofclaim 23, wherein at least a portion of each haptic is rigid.
 27. Thelens of claim 23, wherein the optic is circular.
 28. The lens of claim23, wherein the haptics are connected to and extend from an outer edgeof the optic.
 29. The lens of claim 23, wherein the lens is formed of asingle piece of material.
 30. The lens of claim 23, wherein two hapticsextend from opposite sides of the optic.
 31. The lens of claim 23,wherein three haptics are spaced apart an equal distance from each otheraround the optic.
 32. The lens of claim 23, wherein the haptics includeopposed longitudinal edges that taper inwardly as they extend from theoptic.
 33. The lens of claim 23, wherein the haptics include upper andlower surface that taper inwardly as they extend from the optic.
 34. Thelens of claim 23, wherein the haptics include a lower surface that isconvexly curved.
 35. The lens of claim 34, wherein the haptics lowersurface extends rearwardly beyond a posterior surface of the optic. 36.The lens of claim 23, wherein each haptic includes an outer end and saidouter portion includes a pair of fingers that extend from the outer end.37. The lens of claim 36, wherein the fingers are relatively straight intheir unstressed state.
 38. The lens of claim 36, wherein the fingersare curved inwardly in their unstressed state.
 39. The lens of claim 36,wherein the fingers are formed integrally with each haptic.
 40. The lensof claim 36, wherein the fingers are attached to the outer end of eachhaptic.
 41. The lens of claim 36, wherein the fingers extend from theouter end of each haptic.
 42. The lens of claim 36, wherein the fingersextend from opposite sides of each haptic.
 43. The lens of claim 36,wherein the fingers include an enlarged portion adapted to beencapsulated by the inner surface of the eye so as to hold the hapticsin place relative to the inner surface of the eye when the inner surfaceof the eye expands and contracts.
 44. The lens of claim 43, wherein theenlarged portion is a knob.
 45. An accommodating intraocular lens forimplantation into a generally circular inner surface of an eye,comprising: (a) an optic; (b) at least two haptics spaced apart fromeach other and extending generally radially away from the optic, adaptedto engage the generally circular inner surface of the eye for holdingthe lens in the eye; (c) each of the haptics including an outer portionwith a surface adapted to engage the generally circular inner surface ofthe eye, at least part of said outer surface extending beyond thediameter of the generally circular inner surface of the eye, when saidouter portion is in its unstressed state, said outer portion beingflexible and not conforming to the generally circular inner surface ofthe eye until subjected to compressive forces, so that the outer surfacewill conform generally to the shape of the inner surface of the eye whensubjected to said compression forces upon implantation, said outerportion shaped to be encapsulated by the inner surface of the eye so asto hold the haptics in place relative to the inner surface of the eyewhen the inner surface of the eye expands and contracts; and (d) thehaptics being flexible along at least a portion of their respectivelengths to move the optic anteriorly and/or posteriorly in response toforces imparted to the lens through contraction and expansion of thegenerally circular inner surface of the eye.
 46. The lens of claim 45,wherein said outer portion is T-shaped, the T-shaped outer portionhaving two free ends.
 47. The lens of claim 46, wherein the free endsinclude enlarged portions.
 48. The lens of claim 46, wherein at leastone of the free ends is knob shaped.
 49. The lens of claim 46, whereinat least one of the free ends of disc shaped.
 50. The lens of claim 45,wherein each haptic includes at least one hinge adapted to allow theoptic to move posteriorly when the inner surface of the eye expands andto move anteriorly when the inner surface contracts.
 51. The lens ofclaim 50, wherein said at least one of the hinges is a reduced portionof the haptic.
 52. The lens of claim 50, wherein the hinge has anelastic memory operable to bias the hinge back to its normallyunstressed position following contractions or expansion of the innersurface of the eye.